1. Field of the Invention
The present invention relates to a storage, and in particular to a disk array apparatus which stores data in one or more disk devices, and a storage system including plural disk array apparatuses.
2. Description of the Related Art
Sizes of storages used in companies and the like are increasing year after year. In order to cope with this increase in sizes, a technique called a disk array, which connects plural storages and operates the storages as one storage system, has been devised.
FIG. 2 is a diagram showing an example of a structure of a conventional disk array apparatus (U.S. Pat. No. 6,477,619). As shown in FIG. 2, the disk array apparatus includes plural storages (here, disk devices) 202 and a disk control apparatus 210 that controls the plural storages 202. The disk control apparatus 210 includes: channel interface (hereinafter referred to as “channel IF”) units 204 for performing data transfer between a computer, which uses the disk array apparatus, and the disk control apparatus 210; disk interface (hereinafter referred to as “disk IF”) units 205 that execute data transfer between the disk devices 202 and the disk control apparatus 210; and memory units 208 that are cache memories storing data read and written between channel IFs and disk IFs or shared memories storing control information on a disk array (e.g., control information on data transfer between the channel IF units 204 and cache memories). Further, the channel IF units 204, the disk IF units 205, and the memory units 208 are connected to one another by a mutual connecting network 207.